From patchwork Fri Sep 6 13:43:52 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. Wysocki" X-Patchwork-Id: 273200 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 5BE822C0101 for ; Fri, 6 Sep 2013 23:37:02 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751832Ab3IFNgT (ORCPT ); Fri, 6 Sep 2013 09:36:19 -0400 Received: from hydra.sisk.pl ([212.160.235.94]:36751 "EHLO hydra.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751625Ab3IFNgS (ORCPT ); Fri, 6 Sep 2013 09:36:18 -0400 Received: from vostro.rjw.lan (adtl83.neoplus.adsl.tpnet.pl [79.185.223.83]) by hydra.sisk.pl (Postfix) with ESMTPSA id AE157E3DE3; Fri, 6 Sep 2013 15:30:24 +0200 (CEST) From: "Rafael J. Wysocki" To: Alex Williamson Cc: ACPI Devel Maling List , Bjorn Helgaas , LKML , Linux PCI , Yinghai Lu , Jiang Liu , Mika Westerberg , "Kirill A. Shutemov" Subject: [PATCH 1/2] ACPI / hotplug / PCI: Avoid doing too much for spurious notifies Date: Fri, 06 Sep 2013 15:43:52 +0200 Message-ID: <1831138.AvDtjG8RWn@vostro.rjw.lan> User-Agent: KMail/4.10.5 (Linux/3.11.0-rc7+; KDE/4.10.5; x86_64; ; ) In-Reply-To: <2228690.GcUDD3xFfP@vostro.rjw.lan> References: <26431283.HJCKsss0rt@vostro.rjw.lan> <1599165.8kjc3DtEzc@vostro.rjw.lan> <2228690.GcUDD3xFfP@vostro.rjw.lan> MIME-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org From: Rafael J. Wysocki Sometimes we may get a spurious device check or bus check notify for a hotplug device and in those cases we should avoid doing all of the configuration work needed when something actually changes. To that end, check the return value of pci_scan_slot() in enable_slot() and bail out early if it is 0. This turns out to help reduce the amount of diagnostic output from the ACPIPHP subsystem and speed up boot on at least one system that generates multiple device check notifies for PCIe ports during boot. Reported-by: Alex Williamson Signed-off-by: Rafael J. Wysocki --- drivers/pci/hotplug/acpiphp_glue.c | 35 +++++++++++++++++++++++++++-------- 1 file changed, 27 insertions(+), 8 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Index: linux-pm/drivers/pci/hotplug/acpiphp_glue.c =================================================================== --- linux-pm.orig/drivers/pci/hotplug/acpiphp_glue.c +++ linux-pm/drivers/pci/hotplug/acpiphp_glue.c @@ -542,12 +542,12 @@ static void __ref enable_slot(struct acp struct acpiphp_func *func; int max, pass; LIST_HEAD(add_list); + int nr_found; list_for_each_entry(func, &slot->funcs, sibling) acpiphp_bus_add(func_to_handle(func)); - pci_scan_slot(bus, PCI_DEVFN(slot->device, 0)); - + nr_found = pci_scan_slot(bus, PCI_DEVFN(slot->device, 0)); max = acpiphp_max_busnr(bus); for (pass = 0; pass < 2; pass++) { list_for_each_entry(dev, &bus->devices, bus_list) { @@ -566,8 +566,11 @@ static void __ref enable_slot(struct acp } } } - __pci_bus_assign_resources(bus, &add_list, NULL); + /* Nothing more to do here if there are no new devices on this bus. */ + if (!nr_found && (slot->flags & SLOT_ENABLED)) + return; + acpiphp_sanitize_bus(bus); acpiphp_set_hpp_values(bus); acpiphp_set_acpi_region(slot);